package org.bouncycastle.asn1.x509;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.DERSequence;

/**
 * The extendedKeyUsage object.
 * 
 * <pre>
 *      extendedKeyUsage ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
 * </pre>
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class ExtendedKeyUsage extends ASN1Encodable {
    Hashtable usageTable = new Hashtable();
    ASN1Sequence seq;

    public static ExtendedKeyUsage getInstance(ASN1TaggedObject obj,
            boolean explicit) {
        return getInstance(ASN1Sequence.getInstance(obj, explicit));
    }

    public static ExtendedKeyUsage getInstance(Object obj) {
        if (obj instanceof ExtendedKeyUsage) {
            return (ExtendedKeyUsage) obj;
        }

        if (obj instanceof ASN1Sequence) {
            return new ExtendedKeyUsage((ASN1Sequence) obj);
        }

        if (obj instanceof X509Extension) {
            return getInstance(X509Extension
                    .convertValueToObject((X509Extension) obj));
        }

        throw new IllegalArgumentException("Invalid ExtendedKeyUsage: "
                + obj.getClass().getName());
    }

    public ExtendedKeyUsage(KeyPurposeId usage) {
        this.seq = new DERSequence(usage);

        this.usageTable.put(usage, usage);
    }

    public ExtendedKeyUsage(ASN1Sequence seq) {
        this.seq = seq;

        Enumeration e = seq.getObjects();

        while (e.hasMoreElements()) {
            Object o = e.nextElement();
            if (!(o instanceof DERObjectIdentifier)) {
                throw new IllegalArgumentException(
                        "Only DERObjectIdentifiers allowed in ExtendedKeyUsage.");
            }
            this.usageTable.put(o, o);
        }
    }

    public ExtendedKeyUsage(Vector usages) {
        ASN1EncodableVector v = new ASN1EncodableVector();
        Enumeration e = usages.elements();

        while (e.hasMoreElements()) {
            DERObject o = (DERObject) e.nextElement();

            v.add(o);
            this.usageTable.put(o, o);
        }

        this.seq = new DERSequence(v);
    }

    public boolean hasKeyPurposeId(KeyPurposeId keyPurposeId) {
        return (usageTable.get(keyPurposeId) != null);
    }

    /**
     * Returns all extended key usages. The returned vector contains
     * DERObjectIdentifiers.
     * 
     * @return A vector with all key purposes.
     */
    public Vector getUsages() {
        Vector temp = new Vector();
        for (Enumeration it = usageTable.elements(); it.hasMoreElements();) {
            temp.addElement(it.nextElement());
        }
        return temp;
    }

    public int size() {
        return usageTable.size();
    }

    public DERObject toASN1Object() {
        return seq;
    }
}
